Electronic devices have become synonymous with modern life. In many cases, electronic devices are portable, and thus require portable power sources such as batteries, fuel cells and the like. Since no known portable power source lasts forever, it may become necessary, at some point during the life of the electronic device, to replace the portable power source.
Some electronic devices, such as some sensors and/or actuators, can be disposed or otherwise located in remote positions that make power source monitoring and/or replacement difficult. In important or even critical devices, one may be forced to replace the portable power source on a regular schedule, regardless of the remaining capacity of the power sources. While this technique may help ensure an ongoing power supply, the power sources may be replaced sooner than necessary and thus this technique may be viewed as wasteful. In less important devices, one may simply wait and replace the portable power source when the portable power source no longer provides sufficient energy to power the device.
A need remains for improved portable power sources that can provide an indication of their remaining capacity. A need also remains for ways to remotely communicate with portable power sources, and in particular, remotely monitor an indication of the remaining capacity of such power sources.